System for connecting a first component and a second component to form a flexurally rigid frame corner

ABSTRACT

The invention relates to a system for connecting a first load-bearing component ( 1 ) to a second load-bearing component ( 2 ) in order to form a flexurally rigid frame corner, having a first connecting plate ( 12 ), which is arranged on the first component ( 1 ), and a second connecting plate ( 22 ), which is arranged on the second component ( 2 ), wherein
         a. the connecting plates ( 12, 22 ) each contain a first bore, in which a bolt element ( 3 ) is introduced in order to form a defined axis of rotation,   b. the connecting plates ( 12, 22 ) contain further, mutually correspondingly arranged apertures ( 14, 24 ), in which is arranged at least one screw ( 4 ) which braces the connecting plates ( 12, 22 ) against one another, and   c. the further apertures ( 14, 24 ) and the at least one screw ( 4 ) are dimensioned such that rotation is possible through a defined angle of rotation about the axis of rotation.

The invention relates to a system for connecting a first component and asecond component in order to form a flexurally rigid frame corner. Thesystem is provided, in particular, for use on or in buildings, inparticular buildings in earthquake regions.

DD 290 464 A5 relates to a mechanical damping element for vibrationwhich occurs between a foundation and an object located thereon inregions which are vulnerable to earthquakes. The damping element has abaseplate on which steel balls which are arranged at the corner pointsof the object can move horizontally, the steel balls being enclosed, inthe movement directions, by resilient material. The running-surface sideof the steel balls is free of the elastic-plastic material.

DE 34 02 449 C2 relates to an apparatus for damping vibration ontower-like structures, having a pendulum, with a pendulum rod, which issuspended on a cantilever support of the structure, for executingthree-dimensional vibration, under which the lower end penetratesloosely in an upwardly open cavity of a frictional weight. Thefrictional weight is made up of a plurality of non-connectedcircular-disk-form friction plates which are stacked one upon the otherand of which the external diameter increases from the upper plate to thelower plate. The lowermost plate is mounted in a displaceable manner ona base, and the cavity is formed by central holes in the frictionplates, wherein the hole diameter increases from the upper frictionplate to the lower friction plate.

DE 43 05 132 C1 relates to a friction damper for securing load-bearingstructures against dynamic effects, having at least two friction plateswhich are arranged one above the other, make contact along curvedcontact surfaces and are connected in alternating fashion to a first orsecond of two friction-damper connections. A pre-tensioning means forthe friction plates arranged one above the other is provided.

DE 10 2007 051 285 A1 relates to a fastening bracket having a first anda second fastening limb, which are connected to one another via adeformation element, and therefore the first fastening limb can bedisplaced in relation to the second fastening limb with the deformationelement being deformed in the process.

EP 1 170 429 A1 relates to a vibration-counteracting reinforcing holderhaving a base part which is formed by the two end parts of a plate beingrotated and bent in one direction. Fastening pieces are thus formed onthe reinforcing holder. Absorber parts, which have rubber elasticity andvia which the base part is fixed on structural parts, are provided.

EP 1 164 225 A1 relates to a vibration-counteracting metal fitting,having an L-shaped base part which is formed by virtue of a plate beingbent, and has bent and projecting parts, with inward bending in theintermediate regions of the two parts. A reinforcing part is formed byvirtue of a plate being bent and is in contact with a bent part of theL-shaped base part. Absorption parts made of a rubber material arearranged at various locations of the L-shaped base part.

In frames with so-called flexurally rigid frame corners in the framecorners, all horizontal loads have to be absorbed and passed on. Theconnection between the so-called posts and crossmembers, on the onehand, therefore has to have a very high level of rigidity, so that windalone does not cause the structure to vibrate excessively; on the otherhand, the connection also has to allow deformation to the extent where,in the case of an earthquake, failure does not occur, that is to say theflexurally rigid frame corners do not collapse.

If use is made of flexurally rigid frame corners, these have the greatadvantage over stiffening plates that free and variable utilization ofground-plan space is made possible.

It is an object of the present invention to provide a system which makesit possible to provide, along with straightforward assembly, a highlevel of safety and effectiveness for structures.

This object is achieved according to the invention by a system havingthe features of the main claim. Advantageous configurations anddevelopments of the invention are given in the dependent claims, thedescription and the figures.

The system according to the invention for connecting a first componentand a second component in order to form a flexurally rigid frame corner,having a first connecting plate, which is arranged on the firstcomponent, and a second connecting plate, which is arranged on thesecond component, provides that the connecting plates each contain afirst bore, in which a bolt element is introduced in order to form adefined axis of rotation, that the connecting plates contain further,correspondingly arranged apertures, in which is arranged at least onescrew which braces the connecting plates against one another, and thatthe further apertures and the at least one screw are dimensioned suchthat rotation is possible through a defined angle of rotation about theaxis of rotation.

Structural parts in buildings, such as posts and crossmembers, are oftenproduced from wood or metal. Wood has an extremely high load-bearingcapability in relation to its mass, and therefore load-bearingstructures with a low dead weight are possible. This low dead weight isadvantageous, in particular, when earthquakes cause the building tovibrate from the foundations. If structures are then designed with avery high level of rigidity, and the building also has a high mass, veryhigh levels of stressing occur and, with the materials having a lowdissipation potential, these often result in the structure failing. Thedissipation potential in wooden structures, on account of the low levelof plastic deformability, resides not as much in the wood itself as inthe junction points, that is to say in the connections between theindividual components. The invention provides that connecting plates areformed on the individual components, are configured preferably as steelplates and are arranged at the ends of the respective components, andthat these connecting plates, in order to ensure precise positioning ofthe components in relation to one another and also a sufficientcapability to transmit static loading, each contain a first bore, intowhich a matching bolt element is introduced. The bolt element serves forthe secure and precise positioning of the connecting plates in relationto one another and, at the same time, as an axis of rotation, aboutwhich the components can pivot. The connecting plates contain further,or second, correspondingly arranged apertures, for example ones whichhave been milled out, punched out or the like, which in the assembledstate, that is to say the state in which the two connecting plates buttagainst one another, cover over one another at least in part, andtherefore at least one screw, via which the two connecting plates can bebraced against one another, can be arranged through the two apertures orfurther apertures. Said second or further apertures here are dimensionedsuch that rotation is possible through a defined angle of rotation aboutthe axis of rotation defined by the bolt element in the first bores. Theconnecting principle of the system is thus based, in the first instance,on a rotatable coupling between two components and the securing of thelatter in relation to one another in the first instance via frictionwhich is generated between the two connecting plates, preferablyconsisting of steel, by the pre-tensioned, preferably high-strengthscrews. The transmission of the forces and moments for the predominantlyat-rest loads thus takes place, in the first instance, via the frictionbetween the two connecting plates, wherein linear-elastic deformation ispresent in the event of an increase in forces or moments. Energydissipation takes place within the components and the connecting plates;displacement of the connecting plates in relation to one another is notyet taking place. It is only when the loading reaches a high enoughlevel that the static friction is exceeded that energy dissipation takesplace by kinetic friction, in the case of which the connecting platesare rotated in relation to one another about the axis of rotationdefined by the bolt element. The rotation here is defined only by thedimensions or shaping of the further apertures. The larger the aperturein comparison with the tensioning screws, the greater can thedisplacement be until the connecting plates and the tensioning screwscome into direct contact with the peripheries of the further apertures.Up until this contact is made, the connection between the two componentsremains free of plastic material deformation or plastic damage. If thedeformation continues to increase, bearing forces are activated inaddition in order to maintain the connection; the bearing forces areabsorbed by the bolt element and the tensioning screws in the respectiveapertures.

In order to make it possible for the connecting plates to be guided asprecisely as possible relative to one another, the internal diameter ofthe first bores and the external diameter of the bolt element correspondto one another; the aim is a transition fit, a fit with a low level ofplay or a snug fit of the bolt element within the first apertures. Thedimensions of the bolt element and of the first bores here should beselected such that the components can be assembled on site, that is tosay on the construction site, and basic rotatability about the axis ofrotation formed by the bolt element is possible. A low level of play, inline with the dimensions of the bores and of the bolt element, may beprovided for this purpose; relevant lateral displacement in the plane ofthe connecting plates should not be possible. The level of play can beup to 1 mm in the case of large bolt and bore diameters. The first boreand the bolt element are advantageously round.

The internal diameters of the corresponding further apertures areadvantageously larger than the external diameter of the screws whichbrace the connecting plates against one another, this allowing rotationof the connecting plates relative to one another when the staticfriction is exceeded. There is no need here for the internal diameter ofthe two further, or second, apertures to be larger than the externaldiameter of the screws; rather, it is also possible for one connectingplate to have a further aperture with an internal diameter correspondingto, or matching, the external diameter of the screw, whereas only thecorresponding aperture in the second connecting plate is larger.

It is likewise possible for one or both further apertures to beconfigured as slots and have, for example, a curved shape whichcorresponds to the envisaged rotary path of the two components inrelation to one another. It is thus possible to ensure a kind ofguidance of the rotation of the two components by the tensioning screws.The dimensioning and/or shaping of the further apertures define themaximum angle of rotation of the two components in relation to oneanother until such time as material deformation occurs on account of theperipheries of the apertures being in direct contact with the screws.This defines the range and path of the kinetic friction between theconnecting plates for energy dissipation.

The connecting plates are advantageously provided with a definedcoefficient of friction, which is as constant as possible over theservice life of the system, in order for it to be possible to define atthe outset the frictional forces which occur following assembly. On thesurfaces which are directed toward one another, the connecting platesmay be roughened or provided with regular unevennesses, and thistherefore realizes, in the assembled state, a defined coefficient offriction between the two surfaces located one upon the other. The aim isfor the contact surfaces of the connecting plates to have a permanentlydefined coefficient of friction so that it is possible to realize areliable design and a stable construction over the service life of thestructure. The tensioning screws are preferably tightened with such ahigh torque that the static friction between the connecting plates is ata sufficiently high level to absorb the static and dynamic forces duringconventional usage of a building. It is only under extremely highloading, for example in the event of storms or earthquakes, that thestatic-friction forces are exceeded. The material strength of the screwsand of the bolt elements in relation to shearing forces here is greaterthan the static friction applied, and it is therefore possible toprovide for a further safety reserve in the connection between the twocomponents following the kinetic-friction phase.

A development of the invention provides for a sensor device formonitoring the compressive loading between the connecting plates, andtherefore the pressure to which the contact surfaces of the connectingplates are subjected can be monitored on a permanent basis, and there issufficient and defined static friction present between the connectingplates over the useful life of the connection.

The sensor devices may be designed as disks, for example as washersbetween the connecting plates or beneath the screws. It is also possiblefor a transmission element to be assigned to the sensor device or thedisks, this element making it possible, without high-outlay equipment,to measure the compressive force between the connecting plates, thetightening of the screws being adjusted only in the case of thismeasured value falling below a limit value. The transmission can takeplace wirelessly, for example via a radio element or RFID transmissionor via a cable or some other signal conductor. A transponder may bearranged in the sensor device, and this makes it possible, during andafter the screw-connection of the connecting plates, on the one hand toachieve precisely defined pre-tensioning and, in addition, to be able tomonitor, during usage of the connecting system, whether thepre-tensioning is still present.

The individual disks or sensor devices may be assigned markers, and itis therefore possible to determine precisely which screw connection haswhich torque and which static friction is realized at which locationbetween the connecting plates.

It is possible, in principle, for a plurality of connecting plates to bearranged in alternating fashion one behind the other in the axialdirection, in order to be able to absorb high loading.

Exemplary embodiments of the invention will be explained in more detailhereinbelow with reference to the accompanying figures, in which likereference numerals designate like components and:

FIG. 1 shows a schematic illustration of two components in plan view;

FIG. 2 shows a side view of FIG. 1;

FIG. 3 shows a plan view of the components according to FIG. 1 in theassembled state;

FIG. 4 shows a side view of FIG. 3;

FIGS. 5 a-5 d show illustrations of connecting plates on their own;

FIGS. 6 a-6 d show assembled components with connecting plates accordingto FIGS. 5 a to 5 d; and

FIG. 7 shows a schematic illustration of a moment/rotation diagram.

FIG. 1 illustrates a first component 1 made of a wooden beam 11 with aconnecting plate 12 incorporated therein. The wooden beam 11 and theconnecting plate 12 can be screwed to one another, and the connectingplate 12 consists preferably of a steel or some other high-strengthmaterial which can be connected to the beam 11. In order to connect theconnecting plate 12 to the wooden beam 11, a slit is preferably made inthe wooden beam 11, the connecting plate 12 being pushed into said slit;the connecting plate 12 is fixed, and connected permanently, to the beam11 via conventional dowel rods, possibly in conjunction with adhesivesor other fastening elements. Corresponding fastening takes place on asecond component 2, which likewise has a wooden beam 21 with a secondconnecting plate 22 fastened therein or thereon. Instead of a woodenbeam, the posts and crossmembers used may also be made of othermaterials, for example metal, plastics, concrete or the like. Fasteningof the connecting plates 12, 22 on the respective load-bearing members11, 21 takes place in accordance with the materials and the appropriateconnecting methods. It is also possible, in principle, for a pluralityof connecting plates 12, 22 to be arranged on the respectiveload-bearing members 11, 21; it is also possible for a plurality ofconnecting plates 12, 22 to be arranged one behind the other, whereinthe spacings between the connecting plates 12, 22 arranged one behindthe other are dimensioned such that a corresponding connecting plate ofthe other component can be arranged between two connecting plates.

In the exemplary embodiment illustrated, the first connecting plate 11has formed in it a first bore 13, which is positioned centrally betweentwo first apertures 14. The first bore 13 has a diameter which issmaller than the diameter of the circular apertures 14.

A corresponding first bore 23 and correspondingly arranged second orfurther apertures 24 are arranged in the second connecting plate 22.

FIG. 2 shows that the two connecting plates 12, 22 project beyond therespective load-bearing member 11, 21, and therefore the connectingplates 12, 22, for assembly purposes, can be positioned congruently oneabove the other. The second connecting plate 22 here is larger than thefirst connecting plate 12, which has its end side projecting beyond thelongitudinal extent of the first load-bearing member 11.

FIG. 3 illustrates the two components 1, 2 in the assembled state. Itcan be seen from FIG. 3 that, in the assembled state, the two firstbores 13, 23 are aligned with one another. A bolt element 3, of whichthe external diameter essentially corresponds to the internal diameterof the two bores 13, 23 is guided through the bores 13, 23, wherein thedimensions are selected such that the connecting plates can beassembled, rotated and simultaneously precisely positioned in relationto one another. A defined axis of rotation for the two connecting plates12, 22, and thus also for the two components 1, 2, relative to oneanother is thus formed around the bolt element 3.

Tensioning screws 4 are guided through the two further apertures 24,arranged alongside the respectively first bores 13, 23, in order tobrace the connecting plates 12, 22 against one another. FIG. 4 shows theassembled state with the screw 4 guided through. The external diameterof the screw 4 here is smaller than the internal diameter of theapertures 14, 24, and therefore, once the static friction has beenexceeded, with a moment applied about the axis of rotation of the boltelement 3, it is possible for the two components 1, 2 to be displaced inrelation to one another.

A sensor device 5 for determining the compressive force is arrangedbeneath the head of the screw 4, and possibly beneath the nut, andtherefore the force by which the two connecting plates 12, 22 are bracedagainst one another can be monitored on a permanent basis.

Those surfaces of the connecting plates 12, 22 which are in contact areprovided with a surface which has a defined coefficient of friction.This can be achieved by a particular coating or shaping of the surface,for example by surface treatment by way of forming or cutting, forexample by machining. The surfaces of the connecting plates 12, 22 maybe provided with regular unevennesses, in order to be able to achievedefined coefficients of friction. It is likewise possible for thesurface to be configured such that, as the angle of rotation about theaxis of rotation, which coincides with the center axis of the boltelement 3, the coefficient of friction increases, and this thereforemeans that, under low-level loading, the two components 1, 2 can rotatein relation to one another, once a limit loading has been exceeded,until the static friction retains the two components 1, 2 in position;as loading increases beyond the limit value, the moment of resistanceincreases, and it is only when maximum deflection beyond thekinetic-friction range has been reached that there is materialdeformation occurring in the region of the screws 4 and of the boltelement 3.

In the exemplary embodiment illustrated, the sensor elements 5 aredesigned as washers beneath the screw head and the nut of the tensioningscrews 4 and may be provided with a transponder or some othertransmission device, thus allowing wireless monitoring of thecompressive force applied at the respective screw-connection location;it is also possible, in principle, for the disks to be arranged betweenthe connecting plates 12, 22. Should the compressive force decrease overtime, or be reduced as a result of shocks or subsidence, the tensioningscrew 4 can be pre-tensioned further in order for the desired pressureof the contact surfaces of the connecting plates 12, 22 against oneanother to be maintained in a defined manner on a permanent basis.

The geometry of the connection of the two components 1, 2 via theconnecting plates 12, 22 with the bores 13, 23 with identical internaldiameters and the matching diameter for the bolt element 3 makes itpossible for the system to allow deformation without the componentsundergoing plastic deformation. This deformation within the connectiondoes not lead to failure of the flexurally rigid frame corner formed bythe two components 1, 2 being connected to one another. The first bores13, 23 define the axis of rotation and the position of the components 1,2 in relation to one another; the further apertures 14, 24 allowdisplacement about the axis of rotation and bracing of the connectingplates 12, 22 toward one another via tensioning screws 4, and it istherefore possible to achieve reliable connection of the components 1, 2under normal loading, whereas, in the event of earthquakes, thecomponents can be displaced relative to one another about the axis ofrotation without the connection collapsing.

FIGS. 5 a to 5 d show different connecting plates 12, 22, only thoseparts of the connecting plates 12, 22 which project out of theload-bearing members 11, 21 being illustrated. The connecting plate 12of the first component 1, alongside the bore 13, has two round apertures14 with a diameter which is larger than that of the bore 13; the secondconnecting plate 23 has a first bore 23 with a diameter which isidentical to the diameter of the first bore 13 of the first connectingplate 12; the two further apertures 24 are designed as slots, whereinthe central aperture 24 is shorter than the left-hand aperture 24.

In FIG. 5 b, the bores 13, 23 and apertures 14, 24 are formed in theirsymmetry to the arrangement according to FIG. 5 a, and therefore thecorrespondingly formed bores 13, 23 are arranged at the left-hand end ofthe row of apertures 14.

In FIG. 5 c, the bore 13 is arranged centrally between apertures 14, 24,which are arranged symmetrically in relation to the bore, the apertures14 of the first connecting plate 12 are configured as circular bores,and the apertures 24 of the second connecting plate are configured asequal-length slots.

The embodiment of FIG. 5 d corresponds to that of FIG. 5 c, theapertures 24 of the second connecting plate 22 being designed ascircular apertures with a size corresponding to the aperture sizes inthe first connecting plate 13.

FIGS. 6 a to 6 d illustrate the different possibilities for displacementof the components 1, 2, wherein the configuration of the connectingplates 12, 22 corresponds to the configuration in the equivalentlynumbered image of FIG. 5.

It can be seen in FIG. 6 a that, starting from the basic position, inwhich the load-bearing members 11, of the components 1, 2 areperpendicular to one another, pivoting can take place relatively farupward, since the left-hand aperture 24, in the form of a slot, allowscorrespondingly extensive displacement of the second component 2 in theupward direction. FIG. 6 b shows the possible displacement in thecorrespondingly other direction.

In FIG. 6 c, symmetrical displacement can take place over a relativelywide range since the bore 13, 23 is arranged centrally between the slots24, and in the center of the longitudinal extent, and therefore thecomponents 1, 2 can be pivoted uniformly in a defined angle range aboutthe axis of rotation, which is located in the center of the bores 13,23.

In FIG. 6 d, the symmetrical configuration of the round apertures 14, 24and the central arrangement of the bores 13, 23 likewise allowsymmetrical displacement about the starting position, albeit to a lesserextent than in FIG. 6 c.

FIG. 7 illustrates a diagram which shows the transmittable momentplotted in relation to the rotation α. In a first phase I, theconnection between the two components 1, 2 is linear-elastically rigiduntil the static friction has been exceeded. This is followed, in phaseII, by a pronounced kinetic-friction region, which runs more or lesslinearly. With the coefficient of friction graduated over the angle ofrotation α, it is possible for phase II to contain an increase, whichmay be linear, progressive or degressive. At the end of thekinetic-friction phase II, the rotation about the axis of rotation ofthe bores is pronounced enough for the tensioning screws to come intocontact with the peripheries of the apertures 14, 24 and therefore,following rotation about the angles of rotation defined by the shape anddimensioning of the apertures, bearing forces are activated, and thesethen, in turn, result, following initially elastic rotation, in thematerial of the bolt elements 3 and screws 4, in particular steel,starting to creep, which ultimately results in the screws 4, andpossibly the bolt elements 3, breaking. The breaking point of the screws4 here is lower than the strength of the material of the load-bearingmembers; the breaking strength of the bolt elements 3 may be higher thanthat of the screws 4, and therefore, once the screws 4 have broken,further deformation of the structure and of the frame corner ispossible, so that further energy dissipation can take place without thestructural integrity being lost.

1. System for connecting a first load-bearing component (1) to a secondload-bearing component (2) in order to form a flexurally rigid framecorner, having a first connecting plate (12), which is arranged on thefirst component (1), and a second connecting plate (22), which isarranged on the second component (2), wherein a. the connecting plates(12, 22) each contain a first bore, in which a bolt element (3) isintroduced in order to form a defined axis of rotation, b. theconnecting plates (12, 22) contain further, mutually correspondinglyarranged apertures (14, 24), in which is arranged at least one screw (4)which braces the connecting plates (12, 22) against one another, and c.the further apertures (14, 24) and the at least one screw (4) aredimensioned such that rotation is possible through a defined angle ofrotation about the axis of rotation.
 2. System according to claim 1,characterized in that the internal diameter of the first bore (13, 23)and the external diameter of the bolt element (3) correspond to oneanother.
 3. System according to claim 1, characterized in that, in thecase of the correspondingly arranged apertures (14, 24), the internaldiameter of the further aperture is larger than the external diameter ofthe screws (4).
 4. System according to claim 1, characterized in thatthe further apertures (14, 24) are designed as slots.
 5. Systemaccording to claim 1, characterized in that, on the surfaces which aredirected toward one another in the assembled state, the connectingplates (12, 22) have a defined coefficient of friction.
 6. Systemaccording to claim 5, characterized in that, on the surfaces which aredirected toward one another in the assembled state, the connectingplates (12, 22) are roughened or are provided with regular unevennesses.7. System according to claim 1, characterized by the provision of asensor device (5) for monitoring the compressive forces between theconnecting plates (12, 22).
 8. System according to claim 6,characterized in that the sensor device (5) is designed with a wirelesstransmission device.
 9. System according to claim 1, characterized inthat a plurality of connecting plates (12, 22) are arranged inalternating fashion one behind the other in the axial direction of thebolt element (3).
 10. System according to claim 1, characterized in thatthe connecting plates (12, 22) are non-planar.